upload solutions

B/Main.java

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+import java.util.*;
+import java.io.*;
+
+public class Main {
+  static Map<String, String> parent = new HashMap<>();
+
+  static String find(String i) {
+    if (!parent.containsKey(i)) {
+      parent.put(i, i);
+      return i;
+    }
+    if (parent.get(i).equals(i))
+      return i;
+    String root = find(parent.get(i));
+    parent.put(i, root);
+    return root;
+  }
+
+  static boolean union(String a, String b) {
+    String rootA = find(a);
+    String rootB = find(b);
+
+    if (rootA.equals(rootB))
+      return true;
+
+    boolean isNumA = isNumber(rootA);
+    boolean isNumB = isNumber(rootB);
+
+    if (isNumA && isNumB) {
+      return rootA.equals(rootB);
+    }
+
+    if (isNumA) {
+      parent.put(rootB, rootA);
+    } else {
+      parent.put(rootA, rootB);
+    }
+    return true;
+  }
+
+  public static void main(String[] args) throws IOException {
+    Scanner sc = new Scanner(System.in);
+    if (!sc.hasNextInt())
+      return;
+    int n = sc.nextInt();
+
+    String[] seq1 = new String[n];
+    String[] seq2 = new String[n];
+
+    for (int i = 0; i < n; i++)
+      seq1[i] = sc.next();
+    for (int i = 0; i < n; i++)
+      seq2[i] = sc.next();
+
+    boolean possible = true;
+    for (int i = 0; i < n; i++) {
+      if (!union(seq1[i], seq2[i])) {
+        possible = false;
+        break;
+      }
+    }
+
+    System.out.println(possible ? "YES" : "NO");
+  }
+
+  static boolean isNumber(String s) {
+    if (s == null || s.isEmpty())
+      return false;
+    char first = s.charAt(0);
+    return (first >= '0' && first <= '9') || (first == '-' && s.length() > 1);
+  }
+}

B/test1.in

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+3
+3 1 2
+3 1 3

B/test2.in

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+4
+4 5 igrek igrek
+4 iks 3 iks

B/test3.in

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+5
+x 3 x y 3
+x y 2 z 3